Cover Requirement and Stability of Horizontally Bent Buried Pipelines

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Hamdan N. Al-Ghamedy ◽  
Sahel N. Abduljauwad ◽  
Junaid A. Siddiqui ◽  
Naser A. Al-Shayea ◽  
Ibrahim M. Asi
Keyword(s):  
Regression Models ◽  
Three Dimensional ◽  
Specific Weight ◽  
Elastic Instability ◽  
Buried Pipelines ◽  
Element Analysis ◽  
Buckling Modes ◽  
Dependent Variables ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A method of calculating soil cover requirements for horizontally bent buried pipelines is described. In sequence, the results of a comprehensive three-dimensional finite element analysis are used to develop regression models for two dependent variables: maximum allowed temperature change and minimum overburden height. Other variables considered include the pipe diameter and thickness, the radius and angle of the bend, the internal pressure, the fluid specific weight, and the material used. Relationships among the different variables are determined. Finally, the results are checked with respect to several buckling modes to consider elastic instability conditions.

Stability of Vertically Bent Pipelines Buried in Sand

2004 ◽  
Vol 126 (3) ◽  
pp. 382-390 ◽  
Author(s):  
Sahel N. Abduljauwad ◽  
Hamdan N. Al-Ghamedy ◽  
Junaid A. Siddiqui ◽  
Ibrahim M. Asi ◽  
Naser A. Al-Shayea
Keyword(s):  
Internal Pressure ◽  
Three Dimensional ◽  
Computer Software ◽  
Specific Weight ◽  
Bend Angle ◽  
Element Analysis ◽  
Minimum Cover ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

This paper discusses the stability of underground pipelines with preformed vertical bends buried in sandy soil. More specifically, the minimum cover height required to prevent the pipe from bowing under the action of forces due to temperature change and internal pressure is estimated. The variables considered include the pipe and soil materials, diameter, thickness, overburden height, bend radius, bend angle, internal pressure, fluid specific weight, and temperature variation. A comprehensive three-dimensional finite element analysis is carried out. The results are extracted from the output obtained. These results are put in a database which is used to develop general regression models to determine the relationships among the different variables. Different buckling modes are also considered. All of these results and models are entered into a computer software program for ready access.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

scholarly journals Three-Dimensional Finite Element Analysis of Stress Distribution in a Tooth Restored with Full Coverage Machined Polymer Crown

2021 ◽  
Vol 11 (3) ◽  
pp. 1220
Author(s):  
Azeem Ul Yaqin Syed ◽  
Dinesh Rokaya ◽  
Shirin Shahrbaf ◽  
Nicolas Martin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Intraoral Scanner ◽  
Element Analysis ◽  
Dental Ceramic ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Ceramic Crown

The effect of a restored machined hybrid dental ceramic crown–tooth complex is not well understood. This study was conducted to determine the effect of the stress state of the machined hybrid dental ceramic crown using three-dimensional finite element analysis. Human premolars were prepared to receive full coverage crowns and restored with machined hybrid dental ceramic crowns using the resin cement. Then, the teeth were digitized using micro-computed tomography and the teeth were scanned with an optical intraoral scanner using an intraoral scanner. Three-dimensional digital models were generated using an interactive image processing software for the restored tooth complex. The generated models were imported into a finite element analysis software with all degrees of freedom concentrated on the outer surface of the root of the crown–tooth complex. To simulate average occlusal load subjected on a premolar a total load of 300 N was applied, 150 N at a buccal incline of the palatal cusp, and palatal incline of the buccal cusp. The von Mises stresses were calculated for the crown–tooth complex under simulated load application was determined. Three-dimensional finite element analysis showed that the stress distribution was more in the dentine and least in the cement. For the cement layer, the stresses were more concentrated on the buccal cusp tip. In dentine, stress was more on the cusp tips and coronal 1/3 of the root surface. The conventional crown preparation is a suitable option for machined polymer crowns with less stress distribution within the crown–tooth complex and can be a good aesthetic replacement in the posterior region. Enamic crowns are a good viable option in the posterior region.

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